Map Location
0951640
Abstract
This paper aims to investigate the interaction between the perspective of a person in a fixed street
and the different location the person standing at. In the modelling, the point of view of the person is
the key point which connects the location the person standing at and the different buildings. Dependence of the entire model based on the angle. The paper goes on introducing the principles of
Empirical Modelling utilized in the processing of completing this model. At the final stage, the advantages and disadvantages would be given.
1
a software which can provide comprehensive point
of view is necessary. Empirical Modelling is such a
subject to teach students principles and help them
develop some useful software like this mentioned
before. According to the location the person standing at and the directions of this person looking at,
complicated dependencies could be established.
Introduction
This is a paper about an application on Empirical
Modelling about Map Location. What Map Location
is? It is software developed by the tools of EDEN,
like the city map system people usually use to look
for places but there are some differences. To some
extent, the detailed street scene should be showed in
the software, unlike the famous map search engine
GOOGLE EARTH. The extra function of the model
is that there is a point of view of the person standing
in the street himself. The users could not only notice
the specific location of that person, but also see
what this person observed.
1.2
In Empirical Modelling there are a number of
tools and functions can be applied to explore a set of
circumstances. In this project, Eden, Donald, and
Scout could be used. Donald and Scout there two
tools will be used build the entire scene that the project needed. Include the person, the street, buildings,
functional buttons, and two main visualization windows for users. Eden is actually powerful tool to
achieve diverse complex functions. This environment combines the definitive and procedural paradigms [1]. The colour system could make the screen
more clear. Mark the different buildings with colourful shade could essentially help users identify the
map.
The final model should be able to be used as a
web page based software in order to support some
kinds of people who want to find a specific building
or have a previous scan of this city. At the same
time, the focus of this paper will be to critique Empirical Modelling and offer some personal advises to
this programming software and the subject EM.
1.1
The process
Background
2
Time is absolutely a luxury for all of the people
living in the earth. In this case, it does not make any
sence when we waste too much time in searching a
building. Busy people also cannot spend more time
in travelling where they want to go. However, some
pictures on the web page could not supply enough
help as well, pictures of places of interest are static,
the guest only can scan the specific angle to these
buildings, if the guest wants further information, it
is unavailable usually. Behind this rich background,
The Study
This section details the outcomes of the use of
these three tools chosen for the study: Eden, Donald
and Scout. It should be noted that, though the Donald function was used first, it has direct connection
with Scout and Eden. Scout part likes a bridge connected Donald and Eden. Finally, all of the functions should be given an expression by Eden. These
three separated sections actually have closer relationship.
1
2.1
Modelling Using Donald
2.3
Donald could implement all the basic paint function. It has various definitions to most graphics. All
of these graphics based on only one important thing:
coordinates. It has a large scope between (0,0) and
(1024,1024) which could satisfied various demands.
Furthermore, it cleaned itself after the picture was
cited by Scout each time with the order „VIEWPOINT‟. Compare to other programming languages,
like c, JAVA, Donald provides a fast way to draw
graphics, some notations just include one definition
and a coordinates. However, in addition to this, the
point (0,0) starts at the lower left. The rectangle
drew by Donald shows in Fig. 1 below.
Modelling Using Eden
The sections Donald and Scout were used to
help develop the model. The model is from two
view point, one from the head above the person
standing at the street like a camera or a satellite. The
other one is from the person himself. When users
control the location with different various functional
buttons, the two screens of different perspective
both changed at the same time. Figure 3 and Figure
4 show the different perspectives of the model.
Fig. 3 The viewpoint of satellite
Fig. 1 Coloured rectangle
At the same time, a string named “Super Market”
could be labelled on it as well.
2.2
Modelling Using Scout
Scout has the same function with Donald but
more formidable. Unlike Donald, it is unlimited in
drawing a graphic only if the resolution of your own
computer supported. As mentioned above, Scout
contains a capability to „VIEWPORT‟ the picture
drew in Donald. Furthermore, users can define the
function of Scout themselves, to be a text box, a
frame window, or even attach an existed picture in
local computer. It is noteworthy that the (0,0) coordinate starts at the upper left corner different from
Donald. The buttons in the project are showed below in Fig. 2.
Fig. 4 The viewpoint of person
2.3.1
Model Functionality
The model has been developed to allow users
control the person, to observe the whole agents
changing, some of scope for interaction with the
variables. The variables in the code are based on
Donald and Scout for the “person” agent with the
addition of the location coordinate changed. The
whole interface is showed in figure 5.
Fig. 2 Buttons
2
ter than now. For example, when users control the
person walk to the left direction till the end, if he is
facing the bookstore, now the graphic in the viewpoint of person window should be larger than the
person standing in the middle of the street. Similarly,
the graphic of building supermarket should smaller
as well. I tried to achieve this function using four
lines to draw each building instead of a rectangle, in
order to control the dimension of buildings, but
when clicking the turn left or turn right button to let
the person rotating angle of 360, the building resumed unabated. Actually in Empirical Modelling, it
is enough to use these tools to complete this function and it would make this model truer. But the
logic of controlling the size of graphics confused me
a long time. If this difficult has been conquered, the
model must be more useful.
Fig. 5 The whole interface
2.3.2
Dependency in the model
The model has been developed with the Empirical Modelling principal of dependency in mind and
so effort has been made to ensure that variables are
defined such they are calculated based on the value
of some variable to which they are linked [2]. To
realize the model better, the information should be
clear first. This model contains three main bodies.
The person, streets, and objects in streets. Supposed
there is a street with a supermarket, a museum and a
bookstore. These things are just there and do not
change. Then put a living person in street, if he
walks, that is relative motion. With the point of view
in users‟ sight, this person supposed to be a labelled
point on the map. He can see the objects in streets.
What can the person do is walking along the street
wherever he wants. Turning left, turning right, or
turning back. With the movement of his body, the
direction of his face changed, so the view of his eyes
changed. Thirdly, the people can see different buildings in the street such as the supermarket or the museum when he walking around. Users could control
the people on the map to go anywhere in street. This
modelling supplies a chance to users to get an overview of the conditions in the street without being
there himself. With the connection of coordinate,
though the three tools mentioned above, the person,
buildings all have the relationships.
3
Modelling Methods Compared
Although Empirical Modelling has been exited
for about 30 years, the programming language of
Modelling should be maturing gradually. As a new
user to study from zero, obviously, there are plenty
of advantages together with disadvantages.
Eden environment is full of functions defined itself
in addition to allowing features such as dependency.
Unlike C language, users could define the function
as what they like. No statement, no complex definition, only need to explain where this function would
be used. Though from the model developed as part
of this study it isn‟t highlighted as well as it might
be, an important concept in the Empirical Modelling
approach is that the models are agent orientated[3]
rather than focusing on the overall process. The notion of dependency is clearly very helpful in terms
of modelling, some other aspects of EM such it being agent orientated are useful alternatives. The
principles and tools for EM are different to other
approaches to modelling and this method should be
explored in computer field and more large area together with mathematics modelling.
There are some problems when I did this model
and advices to Eden.
The building coordinate built system works using variable as dependency in the model. The buttons have the functions of controlling are made up
of these variables. When users click one button for
an action of that person, the whole coordinate
changes because all of the points change, so that the
graphics in the viewpoint windows change.
It did not type check or validate a reference to a
procedure when it was submitted although there are
some tips saying “phrase error”. No type checking
and being allowed to switch a variable that has not
been declared from an „int‟ to a „real‟ was a power
feature because it gives more freedom to the author
of the model. However, this brings with it a set of
problems that are probably the reason type checking
has been introduced in modern programming languages. A miss spelt variable name would be readily
accepted by the Eden parser and take plenty of time
On one hand, although sometimes some coordinates do not change with other points, this does not
impact the dependency in the model since it is not
necessary. For this aspect explained the model being
studied. On the other hand, the model could be bet-
3
to identify as the cause of unexpected behaviour in
the model [2].
As an original creation modelling language, although it was based on C language, compare with C,
it improved a lot. To the user of this language, a
graphical interface is quite necessary. For some reason of modelling, choosing to draw a line is more
convenient than drawing two pints to take shape of a
line. Marked on the scale at the interface is also a
good way to help uses to draw graphics.
4
Conclusion
Overall, the model has been finished using the
principles and agents, dependency in Empirical
Modelling rather than traditional modelling methods.
Possible extensions are mentioned in section 2.3.2.
The model would supply the ideas to build a multifunctional map system by providing the point of
view of the observer‟s perspective.
References
[1] P. Fishwick (1994), Simulation and Model Execution, available from the World Wide Web:
http://www.cis.ufl.edu/~fishwick/book/book.html
(accessed 22/01/05)
[2] The First Warwick Empirical Modelling Bulletin
(WEB-EM-1), Car Interaction at Roundabouts(2001). available from the World Wide Web:
http://www2.warwick.ac.uk/fac/sci/dcs/research/em/
publications/web-em/01/carinteraction.pdf
[3] M. Beynon, National Weather Service (2004), A
Short History of the NWS Warning Event Simulator,
available
from the World Wide Web:
http://www.wdtb.noaa.gov/DLCourses/wes/weshisto
ry.html (accessed 23/01/05)
4